XXXIX THE BARBARIANS BREAK THE EMPIRE INTO EAST AND WEST Throughout the third century the Roman Empire, decaying socially and disintegrating morally, faced the barbarians. The emperors of this period were fighting military autocrats, and the capital of the empire shifted with the necessities of their military policy. Now the imperial headquarters would be at Milan in north Italy, now in what is now Serbia at Sirmium or Nish, now in Nicomedia in Asia Minor. Rome halfway down Italy was too far from the centre of interest to be a convenient imperial seat. It was a declining city. Over most